feedbackd-device-themes: init at 0.8.3

Separate it from `feedbackd` for the following reasons:
- Previously the update script did not see this "package" and did not update it
- Now we can run the test suite of `feedbackd-device-themes`
- This allows a user to only change a device theme, while not recompiling `feedbackd`
- Updating only `feedbackd-device-themes` would result in an awkward commit message where we would claim to update a seemingly non-existing package
- Previous commits that updated both `feedbackd` and `feedbackd-device-themes` at the same time did not mention the update to `feedbackd-device-themes` in the title of the commit message
- They are separate projects after all, with the only direct dependency between the two packages existing in the test suite of `feedbackd-device-themes`
- [Most other distributions also package this package](https://repology.org/project/feedbackd-device-themes/versions) separately from feedbackd

nixos/modules/programs/feedbackd.nix

@@ -17,10 +17,15 @@ in
         Your user needs to be in the `feedbackd` group to trigger effects
       '';
       package = lib.mkPackageOption pkgs "feedbackd" { };
+      theme-package = lib.mkPackageOption pkgs "feedbackd-device-themes" {
+        nullable = true;
+      };
     };
   };
   config = lib.mkIf cfg.enable {
-    environment.systemPackages = [ cfg.package ];
+    environment.systemPackages = [
+      cfg.package
+    ] ++ (if cfg.theme-package != null then [ cfg.theme-package ] else [ ]);
 
     services.dbus.packages = [ cfg.package ];
     services.udev.packages = [ cfg.package ];

pkgs/by-name/fe/feedbackd-device-themes/package.nix

@@ -0,0 +1,56 @@
+{
+  lib,
+  stdenv,
+  fetchFromGitLab,
+  meson,
+  ninja,
+  json-glib,
+  feedbackd,
+  nix-update-script,
+}:
+
+stdenv.mkDerivation (finalAttrs: {
+  pname = "feedbackd-device-themes";
+  version = "0.8.3";
+
+  src = fetchFromGitLab {
+    domain = "gitlab.freedesktop.org";
+    owner = "agx";
+    repo = "feedbackd-device-themes";
+    rev = "v${finalAttrs.version}";
+    hash = "sha256-z+A2G1g2gNfC0cVWUO/LT3QVvXeotcBd+5UEpEtcPfY=";
+  };
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    json-glib # Provides json-glib-validate
+  ];
+
+  nativeCheckInputs = [
+    feedbackd # Provides fbd-theme-validate
+  ];
+
+  mesonFlags = [
+    (lib.mesonOption "validate" (if finalAttrs.doCheck then "enabled" else "disabled"))
+  ];
+
+  doCheck = true;
+
+  passthru = {
+    updateScript = nix-update-script { };
+  };
+
+  strictDeps = true;
+
+  meta = with lib; {
+    description = "Device specific feedback themes for Feedbackd";
+    homepage = "https://gitlab.freedesktop.org/agx/feedbackd-device-themes";
+    license = licenses.gpl3Plus;
+    maintainers = with maintainers; [
+      pacman99
+      Luflosi
+    ];
+    platforms = platforms.linux;
+  };
+})

pkgs/by-name/fe/feedbackd/package.nix

@@ -20,18 +20,10 @@
   dbus,
   gmobile,
   umockdev,
+  feedbackd-device-themes,
   nix-update-script,
 }:
 
-let
-  themes = fetchFromGitLab {
-    domain = "gitlab.freedesktop.org";
-    owner = "agx";
-    repo = "feedbackd-device-themes";
-    rev = "v0.8.3";
-    hash = "sha256-z+A2G1g2gNfC0cVWUO/LT3QVvXeotcBd+5UEpEtcPfY=";
-  };
-in
 stdenv.mkDerivation (finalAttrs: {
   pname = "feedbackd";
   version = "0.8.2";
@@ -93,7 +85,6 @@ stdenv.mkDerivation (finalAttrs: {
   postInstall = ''
     mkdir -p $out/lib/udev/rules.d
     sed "s|/usr/libexec/|$out/libexec/|" < $src/data/90-feedbackd.rules > $out/lib/udev/rules.d/90-feedbackd.rules
-    cp ${themes}/data/* $out/share/feedbackd/themes/
   '';
 
   postFixup = ''